The present invention relates generally to laser illuminating apparatus, and more particularly to a catheter type laser illuminating apparatus, equipped with a diagnostic ultrasonic transducer and a medical-treatment laser transmission fiber. In use, the apparatus is inserted into an artery blood vessel so as to thermally melt, or remove, an atheroma which narrows or closes the blood vessel.
A catheter type laser illuminating apparatus, disclosed in "O Plus E" No. 109, P75-81, 1988, PO63-3834, will be described hereinbelow with reference to FIG. 1. In FIG. 1, a catheter 51 includes an inside hole 52 for injecting a transparent flush agent, an endscope fiber 53, a laser transmission fiber 54, and a balloon 55 on the exterior of the catheter. Characters A and B represent a blood vessel and an atheroma, respectively. In operation, the catheter 51 is first inserted into the blood vessel A and moved so that its top or distal portion is positioned at the vicinity of the atheroma B. Secondly, the balloon 55 is inflated in order to stop the flow of the blood, and a transparent flush agent such as a physiological brine is injected through the injection hole 52 into the blood vessel A. Thereafter, the endscope fiber 53 is used in order to check the position of the catheter 51 in relation to the atheroma B and further to check the state of the atheroma B. The position of the catheter 51 with respect to the atheroma B can then be adjusted so as to allow a medical treatment. In this state, laser light such as YAG laser light is emitted from the top portion of the laser fiber 54 toward the atheroma B which is in turn is melted and removed thermally. Here, the laser illumination to the atheroma B is repeatedly performed under the condition of successively checking the melting state of the atheroma B, because the melting speed and melting state of the atheroma depends upon the laser illuminating power, laser illuminating time and the like.
Problems arise with such a conventional arrangement. Because the state of the atheroma B is checked through the endscope scanning operation during the laser medical treatment, difficulty is encountered in obtaining sufficient information of the atheroma B in the depth direction. Also, since the transparent flush agent (physiological brine) is injected several times through the injection hole 52 into the blood vessel A, there is the possibility that a large amount of the physiological brine is given with respect to the living body. In addition, if the laser illumination time is long, the laser light can penetrate into the atheroma B so as to damage a normal portion of the blood vessel A due to the laser energy. Moreover, the long laser illumination time can increase the temperature of the anatomy or tissue at the vicinity of the atheroma B. Accordingly, the extremely accurate management is required in terms of the laser illumination time and laser illumination power.